1. Field of the Invention
The present invention relates to an illumination module, and particularly to an illumination module with good heat dissipation characteristic.
2. Description of Related Art
Light-emitting diodes (LED), having advantages of long lifespan, small volume, power saving, low pollution, high reliability, and mass production, etc. are used as a light source in illumination modules. However, LEDs are sensitive to temperature. When the temperature is too high, the light-emitting efficiency of LEDs deteriorates, and the wavelength of the light beams emitted by LEDs shifts (i.e. the color of the light beams shifts). Accordingly, the illumination module using LEDs must have a good heat dissipation design to conduct the heat generated by LEDs when emitting lights, so as to keep LEDs working at a lower temperature to maintain an optical quality of the light beams emitted by LEDs.
Referring to FIG. 1, a conventional LED illumination module 100 includes a plurality of red LEDs 110a, a plurality of green LEDs 110b, a plurality of blue LEDs 110c, a heat conducting block 120, a plurality of heat pipes 130, and a heat dissipation element 140. The red LEDs 110a, the green LEDs 110b, and the blue LEDs 110c are disposed on a surface of the heat conducting block 120. The heat pipe 130 is connected between the heat conducting block 120 and the heat dissipation element 140, and the heat generated by the red LED 110a, the green LED 110b, and the blue LED 110c when emitting light beams is dissipated through the same heat conducting block 120, the heat pipe 130, and the heat dissipation element 140 sequentially. The heat dissipation element 140 has a plurality of heat sinks 142, so that the heat dissipation element 140 has a larger heat dissipation area.
Generally speaking, as the red LED 110a is more sensitive to temperature as compared with the green LED 110b and the blue LED 110c, a conductivity of the heat generated by the red LED 110a must be high enough to avoid the deterioration of the light-emitting efficiency and the shift of the color of the emitted light beam resulting from over-high temperature. However, in the conventional LED illumination module 100, as the heat generated by the red LED 110a, the green LED 110b, and the blue LED 110c is dissipated to the environment through the same heat dissipation element 140, the heat generated by the LEDs of three colors influences one another, which makes the heat conductivities being identical, thus leading to the difficulty in improvement of the conductivity of the heat generated by the red LED 110a. In this manner, although the heat conductivity is sufficient to maintain the blue LED 110c and the green LED 110b working at a normal working temperature, for the red LED 110a, the thermal conductivity is insufficient, thus leading to the problems of the deterioration of the light-emitting efficiency and the shift of the color of the red LED 110a. 